The proposed project tests the hypothesis that one series of biological mediators of a genetic propensity in alcoholism could operate through a decreased acute reaction to the effects of ethanol. This theory would be tested on 72 pairs (144 men) of men aged 21 to 25 matched on demography, % body fat, and drinking history, half of whom have an alcoholic first-degree relative (the FHP group). In Phase 1 potential subjects will be identified through a questionnaire distributed to students and nonacademic staff at the University of California, San Diego surveying relevant background information, drinking histories, and family history of psychiatric disorders. FHP men free of psychiatric disorders or alcohol or drug abuse and matched controls will, individually, be invited to the laboratory for 3 test sessions where they will consume (in a random order) placebo or 0.75 m1/kg or 1.25 m1/kg of ethanol. Differences between FHP and FHN men will then be observed through tests of cognitive, psychomotor, and physiological reactions and through auditory evoked potential recordings. Data analysis will attempt to determine whether, in light of pilot data, FHP men are less responsive to the acute effects of ethanol and to pinpoint the specific aspects of the group differences which are most important. Positive results in this investigation could increase our level of understanding of why certain individuals may be at high risk for alcoholism which inturn could point towards the development of more specific prevention and treatment approaches.